The development of new dental alloys relies heavily on the availability of basic data on the constitution and structure of the various binary alloy systems. Ideally, this data should comprise information on all possible binary combinations. The industry, however, uses rare and expensive materials such as gold or the noble metals which are of little interest to many other industrial users. Thus, the alloys of interest in dentistry are not likely to be of great interest elsewhere and, consequently, there is a serious lack of data such as "phase diagrams". This study attempts to supply such data in a systematic manner and in a form which is most convenient to the designer of new alloys.